Traditionally, most commercially available inkjet printers have a print engine which forms part of the overall structure and design of the printer. In this regard, the body of the printer unit is typically constructed to accommodate the printhead and associated media delivery mechanisms, and these features are integral with the printer unit.
This is especially the case with inkjet printers that employ a printhead that traverses back and forth across the media as the media is progressed through the printer unit in small iterations. In such cases the reciprocating printhead is typically mounted to the body of the printer unit such that it can traverse the width of the printer unit between a media input roller and a media output roller, with the media input and output rollers forming part of the structure of the printer unit. With such a printer unit it may be possible to remove the printhead for replacement, however the other parts of the print engine, such as the media transport rollers, control circuitry and maintenance stations, are typically fixed within the printer unit and replacement of these parts is not possible without replacement of the entire printer unit.
As well as being rather fixed in their design construction, printer units employing reciprocating type printheads are relatively slow, particularly when performing print jobs of full colour and/or photo quality. This is due to the fact that the printhead must continually traverse the stationary media to deposit the ink on the surface of the media and it may take a number of swathes of the printhead to deposit one line of the image.
Recently, it has been possible to provide a printhead that extends the entire width of the print media so that the printhead can remain stationary as the media is transported past the printhead. Such systems greatly increase the speed at which printing can occur as the printhead no longer needs to perform a number of swathes to deposit a line of an image, but rather the printhead can deposit the ink on the media as it moves past at high speeds. Such printheads have made it possible to perform full colour 1600 dpi printing at speeds in the vicinity of 60 pages per minute, speeds previously unattainable with conventional inkjet printers.
A crucial aspect of inkjet printing is maintaining the printhead in an operational printing condition throughout its lifetime. A number of factors may cause an inkjet printhead to become non-operational and it is important for any inkjet printer to include a strategy for preventing printhead failure and/or restoring the printhead to an operational printing condition in the event of failure. Printhead failure may be caused by, for example, printhead face flooding, dried-up nozzles (due to evaporation of water from the nozzles—a phenomenon known in the art as decap), or particulates fouling nozzles.
In our earlier applications U.S. Ser. No. 11/246676, filed Oct. 11, 2005, we described a maintenance station for a pagewidth printhead, which addresses some of the shortcomings of traditional maintenance stations used for scanning printheads. The maintenance station described relies on a peeling action of a deformable pad, which unblocks nozzles and cleans ink from the ink ejection face of the printhead. We also described several means for cleaning the pad once a maintenance operation has been performed. For example, ink may be cleaned from the pad by suitable positioning of a wicking element or rocking/rotating the pad into contact with a squeegee or foam cleaner.
It would be desirable to provide a printhead maintenance station, which combines all the advantages of a pad-cleaning action with efficient removal of ink from the pad once a printhead maintenance operation has been performed. It would further be desirable to provide a printhead maintenance station, which can handle relatively large quantities of ink with each maintenance operation. It would further be desirable to provide a printhead maintenance station suitable for a pagewidth printhead, which may span the width of an A4-sized or wider page.